// SPDX-License-Identifier: GPL-2.0-only
/*
 *  GPIO driven matrix keyboard driver
 *
 *  Copyright (c) 2008 Marek Vasut <marek.vasut@gmail.com>
 *
 *  Based on corgikbd.c
 */

#include <linux/types.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/input/matrix_keypad.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/of_platform.h>

struct matrix_keypad {
        const struct matrix_keypad_platform_data *pdata;
        struct input_dev *input_dev;
        unsigned int row_shift;

        DECLARE_BITMAP(disabled_gpios, MATRIX_MAX_ROWS);

        uint32_t last_key_state[MATRIX_MAX_COLS];
        struct delayed_work work;
        spinlock_t lock;
        bool scan_pending;
        bool stopped;
        bool gpio_all_disabled;
};

/*
 * NOTE: If drive_inactive_cols is false, then the GPIO has to be put into
 * HiZ when de-activated to cause minmal side effect when scanning other
 * columns. In that case it is configured here to be input, otherwise it is
 * driven with the inactive value.
 */
static void __activate_col(const struct matrix_keypad_platform_data *pdata,
                           int col, bool on)
{
        bool level_on = !pdata->active_low;

        if (on) {
                gpio_direction_output(pdata->col_gpios[col], level_on);
        } else {
                gpio_set_value_cansleep(pdata->col_gpios[col], !level_on);
                if (!pdata->drive_inactive_cols)
                        gpio_direction_input(pdata->col_gpios[col]);
        }
}

static void activate_col(const struct matrix_keypad_platform_data *pdata,
                         int col, bool on)
{
        __activate_col(pdata, col, on);

        if (on && pdata->col_scan_delay_us)
                udelay(pdata->col_scan_delay_us);
}

static void activate_all_cols(const struct matrix_keypad_platform_data *pdata,
                              bool on)
{
        int col;

        for (col = 0; col < pdata->num_col_gpios; col++)
                __activate_col(pdata, col, on);
}

static bool row_asserted(const struct matrix_keypad_platform_data *pdata,
                         int row)
{
        return gpio_get_value_cansleep(pdata->row_gpios[row]) ?
                        !pdata->active_low : pdata->active_low;
}

static void enable_row_irqs(struct matrix_keypad *keypad)
{
        const struct matrix_keypad_platform_data *pdata = keypad->pdata;
        int i;

        if (pdata->clustered_irq > 0)
                enable_irq(pdata->clustered_irq);
        else {
                for (i = 0; i < pdata->num_row_gpios; i++)
                        enable_irq(gpio_to_irq(pdata->row_gpios[i]));
        }
}

static void disable_row_irqs(struct matrix_keypad *keypad)
{
        const struct matrix_keypad_platform_data *pdata = keypad->pdata;
        int i;

        if (pdata->clustered_irq > 0)
                disable_irq_nosync(pdata->clustered_irq);
        else {
                for (i = 0; i < pdata->num_row_gpios; i++)
                        disable_irq_nosync(gpio_to_irq(pdata->row_gpios[i]));
        }
}

/*
 * This gets the keys from keyboard and reports it to input subsystem
 */
static void matrix_keypad_scan(struct work_struct *work)
{
        struct matrix_keypad *keypad =
                container_of(work, struct matrix_keypad, work.work);
        struct input_dev *input_dev = keypad->input_dev;
        const unsigned short *keycodes = input_dev->keycode;
        const struct matrix_keypad_platform_data *pdata = keypad->pdata;
        uint32_t new_state[MATRIX_MAX_COLS];
        int row, col, code;

        /* de-activate all columns for scanning */
        activate_all_cols(pdata, false);

        memset(new_state, 0, sizeof(new_state));

        /* assert each column and read the row status out */
        for (col = 0; col < pdata->num_col_gpios; col++) {

                activate_col(pdata, col, true);

                for (row = 0; row < pdata->num_row_gpios; row++)
                        new_state[col] |=
                                row_asserted(pdata, row) ? (1 << row) : 0;

                activate_col(pdata, col, false);
        }

        for (col = 0; col < pdata->num_col_gpios; col++) {
                uint32_t bits_changed;

                bits_changed = keypad->last_key_state[col] ^ new_state[col];
                if (bits_changed == 0)
                        continue;

                for (row = 0; row < pdata->num_row_gpios; row++) {
                        if ((bits_changed & (1 << row)) == 0)
                                continue;

                        code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
                        input_event(input_dev, EV_MSC, MSC_SCAN, code);
                        input_report_key(input_dev,
                                         keycodes[code],
                                         new_state[col] & (1 << row));
                }
        }
        input_sync(input_dev);

        memcpy(keypad->last_key_state, new_state, sizeof(new_state));

        activate_all_cols(pdata, true);

        /* Enable IRQs again */
        spin_lock_irq(&keypad->lock);
        keypad->scan_pending = false;
        enable_row_irqs(keypad);
        spin_unlock_irq(&keypad->lock);
}

static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
{
        struct matrix_keypad *keypad = id;
        unsigned long flags;

        spin_lock_irqsave(&keypad->lock, flags);

        /*
         * See if another IRQ beaten us to it and scheduled the
         * scan already. In that case we should not try to
         * disable IRQs again.
         */
        if (unlikely(keypad->scan_pending || keypad->stopped))
                goto out;

        disable_row_irqs(keypad);
        keypad->scan_pending = true;
        schedule_delayed_work(&keypad->work,
                msecs_to_jiffies(keypad->pdata->debounce_ms));

out:
        spin_unlock_irqrestore(&keypad->lock, flags);
        return IRQ_HANDLED;
}

static int matrix_keypad_start(struct input_dev *dev)
{
        struct matrix_keypad *keypad = input_get_drvdata(dev);

        keypad->stopped = false;
        mb();

        /*
         * Schedule an immediate key scan to capture current key state;
         * columns will be activated and IRQs be enabled after the scan.
         */
        schedule_delayed_work(&keypad->work, 0);

        return 0;
}

static void matrix_keypad_stop(struct input_dev *dev)
{
        struct matrix_keypad *keypad = input_get_drvdata(dev);

        spin_lock_irq(&keypad->lock);
        keypad->stopped = true;
        spin_unlock_irq(&keypad->lock);

        flush_delayed_work(&keypad->work);
        /*
         * matrix_keypad_scan() will leave IRQs enabled;
         * we should disable them now.
         */
        disable_row_irqs(keypad);
}

#ifdef CONFIG_PM_SLEEP
static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
{
        const struct matrix_keypad_platform_data *pdata = keypad->pdata;
        unsigned int gpio;
        int i;

        if (pdata->clustered_irq > 0) {
                if (enable_irq_wake(pdata->clustered_irq) == 0)
                        keypad->gpio_all_disabled = true;
        } else {

                for (i = 0; i < pdata->num_row_gpios; i++) {
                        if (!test_bit(i, keypad->disabled_gpios)) {
                                gpio = pdata->row_gpios[i];

                                if (enable_irq_wake(gpio_to_irq(gpio)) == 0)
                                        __set_bit(i, keypad->disabled_gpios);
                        }
                }
        }
}

static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
{
        const struct matrix_keypad_platform_data *pdata = keypad->pdata;
        unsigned int gpio;
        int i;

        if (pdata->clustered_irq > 0) {
                if (keypad->gpio_all_disabled) {
                        disable_irq_wake(pdata->clustered_irq);
                        keypad->gpio_all_disabled = false;
                }
        } else {
                for (i = 0; i < pdata->num_row_gpios; i++) {
                        if (test_and_clear_bit(i, keypad->disabled_gpios)) {
                                gpio = pdata->row_gpios[i];
                                disable_irq_wake(gpio_to_irq(gpio));
                        }
                }
        }
}

static int matrix_keypad_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct matrix_keypad *keypad = platform_get_drvdata(pdev);

        matrix_keypad_stop(keypad->input_dev);

        if (device_may_wakeup(&pdev->dev))
                matrix_keypad_enable_wakeup(keypad);

        return 0;
}

static int matrix_keypad_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct matrix_keypad *keypad = platform_get_drvdata(pdev);

        if (device_may_wakeup(&pdev->dev))
                matrix_keypad_disable_wakeup(keypad);

        matrix_keypad_start(keypad->input_dev);

        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
                         matrix_keypad_suspend, matrix_keypad_resume);

static int matrix_keypad_init_gpio(struct platform_device *pdev,
                                   struct matrix_keypad *keypad)
{
        const struct matrix_keypad_platform_data *pdata = keypad->pdata;
        int i, err;

        /* initialized strobe lines as outputs, activated */
        for (i = 0; i < pdata->num_col_gpios; i++) {
                err = gpio_request(pdata->col_gpios[i], "matrix_kbd_col");
                if (err) {
                        dev_err(&pdev->dev,
                                "failed to request GPIO%d for COL%d\n",
                                pdata->col_gpios[i], i);
                        goto err_free_cols;
                }

                gpio_direction_output(pdata->col_gpios[i], !pdata->active_low);
        }

        for (i = 0; i < pdata->num_row_gpios; i++) {
                err = gpio_request(pdata->row_gpios[i], "matrix_kbd_row");
                if (err) {
                        dev_err(&pdev->dev,
                                "failed to request GPIO%d for ROW%d\n",
                                pdata->row_gpios[i], i);
                        goto err_free_rows;
                }

                gpio_direction_input(pdata->row_gpios[i]);
        }

        if (pdata->clustered_irq > 0) {
                err = request_any_context_irq(pdata->clustered_irq,
                                matrix_keypad_interrupt,
                                pdata->clustered_irq_flags,
                                "matrix-keypad", keypad);
                if (err < 0) {
                        dev_err(&pdev->dev,
                                "Unable to acquire clustered interrupt\n");
                        goto err_free_rows;
                }
        } else {
                for (i = 0; i < pdata->num_row_gpios; i++) {
                        err = request_any_context_irq(
                                        gpio_to_irq(pdata->row_gpios[i]),
                                        matrix_keypad_interrupt,
                                        IRQF_TRIGGER_RISING |
                                        IRQF_TRIGGER_FALLING,
                                        "matrix-keypad", keypad);
                        if (err < 0) {
                                dev_err(&pdev->dev,
                                        "Unable to acquire interrupt for GPIO line %i\n",
                                        pdata->row_gpios[i]);
                                goto err_free_irqs;
                        }
                }
        }

        /* initialized as disabled - enabled by input->open */
        disable_row_irqs(keypad);
        return 0;

err_free_irqs:
        while (--i >= 0)
                free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
        i = pdata->num_row_gpios;
err_free_rows:
        while (--i >= 0)
                gpio_free(pdata->row_gpios[i]);
        i = pdata->num_col_gpios;
err_free_cols:
        while (--i >= 0)
                gpio_free(pdata->col_gpios[i]);

        return err;
}

static void matrix_keypad_free_gpio(struct matrix_keypad *keypad)
{
        const struct matrix_keypad_platform_data *pdata = keypad->pdata;
        int i;

        if (pdata->clustered_irq > 0) {
                free_irq(pdata->clustered_irq, keypad);
        } else {
                for (i = 0; i < pdata->num_row_gpios; i++)
                        free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
        }

        for (i = 0; i < pdata->num_row_gpios; i++)
                gpio_free(pdata->row_gpios[i]);

        for (i = 0; i < pdata->num_col_gpios; i++)
                gpio_free(pdata->col_gpios[i]);
}

#ifdef CONFIG_OF
static struct matrix_keypad_platform_data *
matrix_keypad_parse_dt(struct device *dev)
{
        struct matrix_keypad_platform_data *pdata;
        struct device_node *np = dev->of_node;
        unsigned int *gpios;
        int ret, i, nrow, ncol;

        if (!np) {
                dev_err(dev, "device lacks DT data\n");
                return ERR_PTR(-ENODEV);
        }

        pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata) {
                dev_err(dev, "could not allocate memory for platform data\n");
                return ERR_PTR(-ENOMEM);
        }

        pdata->num_row_gpios = nrow = of_gpio_named_count(np, "row-gpios");
        pdata->num_col_gpios = ncol = of_gpio_named_count(np, "col-gpios");
        if (nrow <= 0 || ncol <= 0) {
                dev_err(dev, "number of keypad rows/columns not specified\n");
                return ERR_PTR(-EINVAL);
        }

        if (of_get_property(np, "linux,no-autorepeat", NULL))
                pdata->no_autorepeat = true;

        pdata->wakeup = of_property_read_bool(np, "wakeup-source") ||
                        of_property_read_bool(np, "linux,wakeup"); /* legacy */

        if (of_get_property(np, "gpio-activelow", NULL))
                pdata->active_low = true;

        pdata->drive_inactive_cols =
                of_property_read_bool(np, "drive-inactive-cols");

        of_property_read_u32(np, "debounce-delay-ms", &pdata->debounce_ms);
        of_property_read_u32(np, "col-scan-delay-us",
                                                &pdata->col_scan_delay_us);

        gpios = devm_kcalloc(dev,
                             pdata->num_row_gpios + pdata->num_col_gpios,
                             sizeof(unsigned int),
                             GFP_KERNEL);
        if (!gpios) {
                dev_err(dev, "could not allocate memory for gpios\n");
                return ERR_PTR(-ENOMEM);
        }

        for (i = 0; i < nrow; i++) {
                ret = of_get_named_gpio(np, "row-gpios", i);
                if (ret < 0)
                        return ERR_PTR(ret);
                gpios[i] = ret;
        }

        for (i = 0; i < ncol; i++) {
                ret = of_get_named_gpio(np, "col-gpios", i);
                if (ret < 0)
                        return ERR_PTR(ret);
                gpios[nrow + i] = ret;
        }

        pdata->row_gpios = gpios;
        pdata->col_gpios = &gpios[pdata->num_row_gpios];

        return pdata;
}
#else
static inline struct matrix_keypad_platform_data *
matrix_keypad_parse_dt(struct device *dev)
{
        dev_err(dev, "no platform data defined\n");

        return ERR_PTR(-EINVAL);
}
#endif

static int matrix_keypad_probe(struct platform_device *pdev)
{
        const struct matrix_keypad_platform_data *pdata;
        struct matrix_keypad *keypad;
        struct input_dev *input_dev;
        int err;

        pdata = dev_get_platdata(&pdev->dev);
        if (!pdata) {
                pdata = matrix_keypad_parse_dt(&pdev->dev);
                if (IS_ERR(pdata))
                        return PTR_ERR(pdata);
        } else if (!pdata->keymap_data) {
                dev_err(&pdev->dev, "no keymap data defined\n");
                return -EINVAL;
        }

        keypad = kzalloc(sizeof(struct matrix_keypad), GFP_KERNEL);
        input_dev = input_allocate_device();
        if (!keypad || !input_dev) {
                err = -ENOMEM;
                goto err_free_mem;
        }

        keypad->input_dev = input_dev;
        keypad->pdata = pdata;
        keypad->row_shift = get_count_order(pdata->num_col_gpios);
        keypad->stopped = true;
        INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
        spin_lock_init(&keypad->lock);

        input_dev->name         = pdev->name;
        input_dev->id.bustype   = BUS_HOST;
        input_dev->dev.parent   = &pdev->dev;
        input_dev->open         = matrix_keypad_start;
        input_dev->close        = matrix_keypad_stop;

        err = matrix_keypad_build_keymap(pdata->keymap_data, NULL,
                                         pdata->num_row_gpios,
                                         pdata->num_col_gpios,
                                         NULL, input_dev);
        if (err) {
                dev_err(&pdev->dev, "failed to build keymap\n");
                goto err_free_mem;
        }

        if (!pdata->no_autorepeat)
                __set_bit(EV_REP, input_dev->evbit);
        input_set_capability(input_dev, EV_MSC, MSC_SCAN);
        input_set_drvdata(input_dev, keypad);

        err = matrix_keypad_init_gpio(pdev, keypad);
        if (err)
                goto err_free_mem;

        err = input_register_device(keypad->input_dev);
        if (err)
                goto err_free_gpio;

        device_init_wakeup(&pdev->dev, pdata->wakeup);
        platform_set_drvdata(pdev, keypad);

        return 0;

err_free_gpio:
        matrix_keypad_free_gpio(keypad);
err_free_mem:
        input_free_device(input_dev);
        kfree(keypad);
        return err;
}

static int matrix_keypad_remove(struct platform_device *pdev)
{
        struct matrix_keypad *keypad = platform_get_drvdata(pdev);

        matrix_keypad_free_gpio(keypad);
        input_unregister_device(keypad->input_dev);
        kfree(keypad);

        return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id matrix_keypad_dt_match[] = {
        { .compatible = "gpio-matrix-keypad" },
        { }
};
MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
#endif

static struct platform_driver matrix_keypad_driver = {
        .probe          = matrix_keypad_probe,
        .remove         = matrix_keypad_remove,
        .driver         = {
                .name   = "matrix-keypad",
                .pm     = &matrix_keypad_pm_ops,
                .of_match_table = of_match_ptr(matrix_keypad_dt_match),
        },
};
module_platform_driver(matrix_keypad_driver);

MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:matrix-keypad");